To deal with the second question first:
Well a single grey wolf just simply wouldn't attack a healthy human adult.
And any hit would scare it off.
So that's not going to bother me in the slightest.
As to the actual question, I'm happy with scenario 2.
Either way, I'll take my EDC sling - as I'll have it anyway - and some spherical/round rocks, approx 150gms/6oz
Pretty much just going to go for head shots.
A direct strike on the bears muzzle or eye will drive it off.
Even hungry predators will actively avoid real injury.
So head strikes are far more likely to be more effective than a body shot.
Not going for razor glandes, or similiar - I have no desire to permanently injure the bear, just don't want to be eaten
Not sure how far the bear is, but I'll start throwing at about 50metres.
I know I can hit a human head at that distance, bear should be a bit easier.
Depending on how much ammo I have I'll probably have a few warning shots starting at 75
metres or so.
So, yep, I reckon I'm walking away from this one
So scenario 3
You're still trapped, but this time you've managed to seriously piss off a bull hippo.
You're basically dead - hippos kill more humans a year than any other wild animal - so is there any way a sling will get you out of the situation ?
You can have a premonition a few days before the actual situation, so as long as it's ammo you can actually make yourself, with stuff you already have around your home - nothing hypothetical - what are you going to be carrying ?
I know what I'd have, and it'd probably give me a 25 percent of survival.
There's just no way you can kill a charging hippo with a sling, so what can you do to escape ?
Oh yeah, it's night - hippos are nocturnal and come on land to feed at night
That helps, if the hippo was in water and you were in a boat, you're dead.